Pisa lies at the junction of two rivers, the Arno and the Serchio, which form a laguna at the Tyrrhenian Sea. The origin of the name, Pisa, is a mystery. While the origin of the city had remained unknown for centuries, the Pelasgi, the Greeks, the Etruscans, and the Ligurians had variously been proposed as founders of the city (for example, a colony of the ancient city of Pisa, Greece). Archaeological remains from the 5th century BC confirmed the existence of a city at the sea, trading with Greeks and Gauls. The presence of an Etruscan necropolis, discovered during excavations in the Arena Garibaldi in 1991, confirmed its Etruscan origins.

Ancient Roman authors referred to Pisa as an old city. Strabo referred Pisa's origins to the mythical Nestor, king of Pylos, after the fall of Troy. Virgil, in his Aeneid, states that Pisa was already a great center by the times described; the settlers from the Alpheus coast have been credited with the founding of the city in the 'Etruscan lands'. The Virgilian commentator Servius wrote that the Teuti, or Pelops, the king of the Pisaeans, founded the town thirteen centuries before the start of the common era.

The maritime role of Pisa should have been already prominent if the ancient authorities ascribed to it the invention of the naval ram. Pisa took advantage of being the only port along the western coast from Genoa (then a small village) to Ostia. Pisa served as a base for Roman naval expeditions against Ligurians, Gauls and Carthaginians. In 180 BC, it became a Roman colony under Roman law, as Portus Pisanus. In 89 BC, Portus Pisanus became a municipium. Emperor Augustus fortified the colony into an important port and changed the name in Colonia Iulia obsequens.

It is supposed that Pisa was founded on the shore. However, due to the alluvial sediments from the Arno and the Serchio, the shore moved west. Strabo states that the city was 4.0 kilometres (2.5 mi) away from the coast. Currently, it is located 9.7 kilometres (6 mi) from the coast. However it was a maritime city, with ships sailing up the Arno.[3]

During the later years of the Roman Empire, Pisa did not decline as much as the other cities of Italy, probably thanks to the complexity of its river system and its consequent ease of defence. In the 7th century Pisa helped Pope Gregory I by supplying numerous ships in his military expedition against the Byzantines of Ravenna: Pisa was the sole Byzantine centre of Tuscia to fall peacefully in Lombard hands, through assimilation with the neighbouring region where their trading interests were prevailing. Pisa began in this way its rise to the role of main port of the Upper Tyrrhenian Sea and became the main trading centre between Tuscany and Corsica, Sardinia and the southern coasts of France and Spain.

After Charlemagne had defeated the Lombards under the command of Desiderius in 774, Pisa went through a crisis but soon recovered. Politically it became part of the duchy of Lucca. In 860, Pisa was captured by vikings led by Björn Ironside. In 930 Pisa became the county centre (status it maintained until the arrival of Otto I) within the mark of Tuscia. Lucca was the capital but Pisa was the most important city, as in the middle of 10th century Liutprand of Cremona, bishop of Cremona, called Pisa Tusciae provinciae caput ("capital of the province of Tuscia"), and one century later the marquis of Tuscia was commonly referred to as "marquis of Pisa". In 1003 Pisa was the protagonist of the first communal war in Italy, against Lucca. From the naval point of view, since the 9th century the emergence of the Saracen pirates urged the city to expand its fleet: in the following years this fleet gave the town an opportunity for more expansion. In 828 Pisan ships assaulted the coast of North Africa. In 871 they took part in the defence of Salerno from the Saracens. In 970 they gave also strong support to the Otto I's expedition, defeating a Byzantine fleet in front of Calabrese coasts.

The power of Pisa as a mighty maritime nation began to grow and reached its apex in the 11th century when it acquired traditional fame as one of the four main historical Maritime Republics of Italy (Repubbliche Marinare).

At that time, the city was a very important commercial centre and controlled a significant Mediterranean merchant fleet and navy. It expanded its powers in 1005 through the sack of Reggio Calabria in the south of Italy. Pisa was in continuous conflict with the Saracens, who had their bases in Corsica, for control of the Mediterranean. In 1017 SardinianGiudicati were militarily supported by Pisa, in alliance with Genoa, to defeat the Saracen King Mugahid who had settled a logistic base in the north of Sardinia the year before. This victory gave Pisa supremacy in the Tyrrhenian Sea. When the Pisans subsequently ousted the Genoese from Sardinia, a new conflict and rivalry was born between these mighty marine republics. Between 1030 and 1035, Pisa went on to defeat several rival towns in Sicily and conquer Carthage in North Africa. In 1051–1052 the admiral Jacopo Ciurini conquered Corsica, provoking more resentment from the Genoese. In 1063 admiral Giovanni Orlando, coming to the aid of the NormanRoger I, took Palermo from the Saracen pirates. The gold treasure taken from the Saracens in Palermo allowed the Pisans to start the building of their cathedral and the other monuments which constitute the famous Piazza del Duomo.

In 1060 Pisa had to engage in their first battle with Genoa. The Pisan victory helped to consolidate its position in the Mediterranean. Pope Gregory VII recognised in 1077 the new "Laws and customs of the sea" instituted by the Pisans, and emperor Henry IV granted them the right to name their own consuls, advised by a Council of Elders. This was simply a confirmation of the present situation, because in those years the marquis had already been excluded from power. In 1092 Pope Urban II awarded Pisa the supremacy over Corsica and Sardinia, and at the same time raising the town to the rank of archbishopric.

Pisa sacked the Tunisian city of Mahdia in 1088. Four years later Pisan and Genoese ships helped Alfonso VI of Castilla to push El Cid out of Valencia. A Pisan fleet of 120 ships also took part in the First Crusade and the Pisans were instrumental in the taking of Jerusalem in 1099. On their way to the Holy Land the ships did not miss the occasion to sack some Byzantine islands: the Pisan crusaders were led by their archbishop Daibert, the future patriarch of Jerusalem. Pisa and the other Repubbliche Marinare took advantage of the crusade to establish trading posts and colonies in the Eastern coastal cities of the Levant. In particular the Pisans founded colonies in Antiochia, Acre, Jaffa, Tripoli, Tyre, Latakia and Accone. They also had other possessions in Jerusalem and Caesarea, plus smaller colonies (with lesser autonomy) in Cairo, Alexandria and of course Constantinople, where the Byzantine EmperorAlexius I Comnenus granted them special mooring and trading rights. In all these cities the Pisans were granted privileges and immunity from taxation, but had to contribute to the defence in case of attack. In the 12th century the Pisan quarter in the Eastern part of Constantinople had grown to 1,000 people. For some years of that century Pisa was the most prominent merchant and military ally of the Byzantine Empire, overcoming Venice itself.

The war began in 1119 when the Genoese attacked several galleys on their way to the motherland, and lasted until 1133. The two cities fought each other on land and at sea, but hostilities were limited to raids and pirate-like assaults.

In June 1135, Bernard of Clairvaux took a leading part in the Council of Pisa, asserting the claims of pope Innocent II against those of pope Anacletus II, who had been elected pope in 1130 with Norman support but was not recognised outside Rome. Innocent II resolved the conflict with Genoa, establishing the sphere of influence of Pisa and Genoa. Pisa could then, unhindered by Genoa, participate in the conflict of Innocent II against king Roger II of Sicily. Amalfi, one of the Maritime Republics (though already declining under Norman rule), was conquered on August 6, 1136: the Pisans destroyed the ships in the port, assaulted the castles in the surrounding areas and drove back an army sent by Roger from Aversa. This victory brought Pisa to the peak of its power and to a standing equal to Venice. Two years later its soldiers sacked Salerno.

New city walls, erected in 1156 by Consul Cocco Griffi

In the following years Pisa was one of the staunchest supporters of the Ghibelline party. This was much appreciated by Frederick I. He issued in 1162 and 1165 two important documents, with the following grants: apart from the jurisdiction over the Pisan countryside, the Pisans were granted freedom of trade in the whole Empire, the coast from Civitavecchia to Portovenere, a half of Palermo, Messina, Salerno and Naples, the whole of Gaeta, Mazara and Trapani, and a street with houses for its merchants in every city of the Kingdom of Sicily. Some of these grants were later confirmed by Henry VI, Otto IV and Frederick II. They marked the apex of Pisa's power, but also spurred the resentment of cities like Lucca, Massa, Volterra and Florence, who saw their aim to expand towards the sea thwarted. The clash with Lucca also concerned the possession of the castle of Montignoso and mainly the control of the Via Francigena, the main trade route between Rome and France. Last but not least, such a sudden and large increase of power by Pisa could only lead to another war with Genoa.

Genoa had acquired a largely dominant position in the markets of Southern France. The war began presumably in 1165 on the Rhône, when an attack on a convoy, directed to some Pisan trade centres on the river, by the Genoese and their ally, the count of Toulouse failed. Pisa on the other hand was allied to Provence. The war continued until 1175 without significant victories. Another point of attrition was Sicily, where both the cities had privileges granted by Henry VI. In 1192, Pisa managed to conquer Messina. This episode was followed by a series of battles culminating in the Genoese conquest of Syracuse in 1204. Later, the trading posts in Sicily were lost when the new Pope Innocent III, though removing the excommunication cast over Pisa by his predecessor Celestine III, allied himself with the Guelph League of Tuscany, led by Florence. Soon he stipulated a pact with Genoa too, further weakening the Pisan presence in Southern Italy.

To counter the Genoese predominance in the southern Tyrrhenian Sea, Pisa strengthened its relationship with their Spanish and French traditional bases (Marseille, Narbonne, Barcelona, etc.) and tried to defy the Venetian rule of the Adriatic Sea. In 1180 the two cities agreed to a non-aggression treaty in the Tyrrhenian and the Adriatic, but the death of Emperor Manuel Comnenus in Constantinople changed the situation. Soon there were attacks on Venetian convoys. Pisa signed trade and political pacts with Ancona, Pula, Zara, Split and Brindisi: in 1195 a Pisan fleet reached Pola to defend its independence from Venice, but the Serenissima managed soon to reconquer the rebel sea town.

One year later the two cities signed a peace treaty which resulted in favourable conditions for Pisa. But in 1199 the Pisans violated it by blockading the port of Brindisi in Apulia. In the following naval battle they were defeated by the Venetians. The war that followed ended in 1206 with a treaty in which Pisa gave up all its hopes to expand in the Adriatic, though it maintained the trading posts it had established in the area. From that point on the two cities were united against the rising power of Genoa and sometimes collaborated to increase the trading benefits in Constantinople.

In 1209 there were in Lerici two councils for a final resolution of the rivalry with Genoa. A twenty-year peace treaty was signed. But when in 1220 the emperor Frederick II confirmed his supremacy over the Tyrrhenian coast from Civitavecchia to Portovenere, the Genoese and Tuscan resentment against Pisa grew again. In the following years Pisa clashed with Lucca in Garfagnana and was defeated by the Florentines at Castel del Bosco. The strong Ghibelline position of Pisa brought this town diametrically against the Pope, who was in a strong dispute with the Empire. And indeed the pope tried to deprive the town of its dominions in northern Sardinia.

In 1238 Pope Gregory IX formed an alliance between Genoa and Venice against the empire, and consequently against Pisa too. One year later he excommunicated Frederick II and called for an anti-Empire council to be held in Rome in 1241. On May 3, 1241, a combined fleet of Pisan and Sicilian ships, led by the Emperor's son Enzo, attacked a Genoese convoy carrying prelates from Northern Italy and France, next to the isle of Giglio (Battle of Giglio), in front of Tuscany: the Genoese lost 25 ships, while about thousand sailors, two cardinals and one bishop were taken prisoner. After this outstanding victory the council in Rome failed, but Pisa was excommunicated. This extreme measure was only removed in 1257. Anyway, the Tuscan city tried to take advantage of the favourable situation to conquer the Corsican city of Aleria and even lay siege to Genoa itself in 1243.

The Ligurian republic of Genoa, however, recovered fast from this blow and won back Lerici, conquered by the Pisans some years earlier, in 1256.

The great expansion in the Mediterranean and the prominence of the merchant class urged a modification in the city's institutes. The system with consuls was abandoned and in 1230 the new city rulers named a Capitano del Popolo ("People's Chieftain") as civil and military leader. In spite of these reforms, the conquered lands and the city itself were harassed by the rivalry between the two families of Della Gherardesca and Visconti. In 1237 the archbishop and the Emperor Frederick II intervened to reconcile the two rivals, but the strains did not cease. In 1254 the people rebelled and imposed twelve Anziani del Popolo ("People's Elders") as their political representatives in the Commune. They also supplemented the legislative councils, formed of noblemen, with new People's Councils, composed by the main guilds and by the chiefs of the People's Companies. These had the power to ratify the laws of the Major General Council and the Senate.

It is said that the decline began on August 6, 1284, when the numerically superior fleet of Pisa, under the command of Albertino Morosini, was defeated by the brilliant tactics of the Genoese fleet, under the command of Benedetto Zaccaria and Oberto Doria, in the dramatic naval Battle of Meloria. This defeat ended the maritime power of Pisa and the town never fully recovered: in 1290 the Genoese destroyed forever the Porto Pisano (Pisa's Port), and covered the land with salt. The region around Pisa did not permit the city to recover from the loss of thousands of sailors from the Meloria, while Liguria guaranteed enough sailors to Genoa. Goods however continued to be traded, albeit in reduced quantity, but the end came when the River Arno started to change course, preventing the galleys from reaching the city's port up the river. It seems also that nearby area became infested with malaria. The true end came in 1324 when Sardinia was entirely lost in favour of the Aragonese.

Always Ghibelline, Pisa tried to build up its power in the course of the 14th century and even managed to defeat Florence in the Battle of Montecatini (1315), under the command of Uguccione della Faggiuola. Eventually, however, after a long siege, Pisa was occupied by Florentines in 1406: in fact florentines corrupted the Capitano del Popolo ("People's Chieftain") Giovanni Gambacorta that opened by night the city gate of San Marco. Pisa was never conquered by an army. In 1409 Pisa was the seat of a council trying to set the question of the Great Schism. Furthermore, in the 15th century, access to the sea became more and more difficult, as the port was silting up and was cut off from the sea. When in 1494 Charles VIII of France invaded the Italian states to claim the Kingdom of Naples, Pisa grabbed the opportunity to reclaim its independence as the Second Pisan Republic.

But the new freedom did not last long. There were fifteen years of battles and sieges by the Florentine troops led by Antonio da Filicaja, Averardo Salviati and Niccolò Capponi but they never managed to conquer the city. Vitellozzo Vitelli with his brother Paolo were the only ones that actually managed to break the strong defences of Pisa and make a breach in the Stampace bastion in the southern west part of the walls, but he did not entered the city. For that they were suspected of treachery and Paolo was put to death. However resources of Pisa were getting low and, at the end, the city was sold to Visconti family from Milan and eventually to Florence again. Its role of major port of Tuscany went to Livorno. Pisa acquired a mainly cultural role spurred by the presence of the University of Pisa, created in 1343, and later reinforced by the Scuola Normale Superiore di Pisa (1810) and Sant'Anna School of Advanced Studies (1987).

Pisa was the birthplace of the important early physicist Galileo Galilei. It is still the seat of an archbishopric. Besides its educational institutions; it has become a light industrial centre and a railway hub. It suffered repeated destruction during World War II.

Since the early 1950s the US Army has maintained Camp Darby just outside Pisa which is used by many US military personnel as a base for vacations in the area.[4][5]

Pisa experiences a Mediterranean climate (Köppen climate classificationCsa) typical of Central and Southern Italy, which is characterized by mild winters and very warm summers. However, Pisa does not have a classic Mediterranean climate. Although summer is the driest season, some rainfall does occur in summer. And autumn, not winter, is the season with maximum precipitation.

While the bell tower of the Cathedral, known as "the leaning Tower of Pisa", is the most famous image of the city, it is one of many works of art and architecture in the city's Piazza del Duomo, also known, since the 20th century, as Piazza dei Miracoli (Square of Miracles), to the north of the old town center. The Piazza del Duomo also houses the Duomo (the Cathedral), the Baptistry and the Campo Santo (the monumental cemetery). The medieval complex includes the above-mentioned four sacred buildings, the hospital and few palaces. All the complex is kept by the Opera (fabrica ecclesiae) della Primaziale Pisana, an old non profit foundation that operates since the building of the Cathedral (1063) to the maintenance of the sacred buildings. The area is framed by medieval walls kept by municipality administration.

Other interesting sights include:

Knights' Square (Piazza dei Cavalieri), where the Palazzo della Carovana, with its impressive façade designed by Giorgio Vasari may be seen. Sited on the square

Church of Santo Stefano dei Cavalieri: Sited on Piazza dei Cavalieri, and also designed by Vasari. It had originally a single nave; two more were added in the 17th century. It houses a bust by Donatello, and paintings by Vasari, Jacopo Ligozzi, Alessandro Fei, and Jacopo Chimenti da Empoli. It also contains spoils from the many naval battles between the Cavalieri (Knights of St. Stephan) and the Turks between the 16th and 18th centuries, including the Turkish battle pennant hoisted from Ali Pacha's flagship at the 1571 Battle of Lepanto.

Church of St. Sixtus: This small church, consecrated in 1133, is also close to the Piazza dei Cavalieri. It was used as a seat of the most important notarial deeds of the town, also hosting the Council of Elders. It is today one of the best preserved early Romanesque buildings in town.

Church of Santa Maria della Spina: This small white marble church alongside the Arno, is attributed to Lupo di Francesco (1230), is another excellent Gothic building.

Church of San Paolo a Ripa d'Arno: The church was founded around 952 and enlarged in the mid-12th century along lines similar to those of the cathedral. It is annexed to the Romanesque Chapel of St. Agatha, with an unusual pyramidal cusp or peak.

Church of San Pietro in Vinculis: The church St Peter in Chains, known as San Pierino, is an 11th-century church with a crypt and a cosmatesque mosaic on the floor of the main nave.

Borgo Stretto: This medieval borgo or neighborhood contains strolling arcades and the Lungarno, the avenues along the river Arno. It includes the Gothic-Romanesque church of San Michele in Borgo (990). Remarkably, there are at least two other leaning towers in the city, one at the southern end of central Via Santa Maria, the other halfway through the Piagge riverside promenade.

Medici Palace: The palace was once a possession of the Appiano family, who ruled Pisa in 1392–1398. In 1400 the Medici acquired it, and Lorenzo de' Medici sojourned here.

Palazzo Gambacorti: This palace is a 14th-century Gothic building, and now houses the offices of the municipality. The interior shows frescoes boasting Pisa's sea victories.

Palazzo Agostini: The palace is a Gothic building also known as Palazzo dell'Ussero, with its 15th-century façade and remains of the ancient city walls dating back to before 1155. The name of the building comes from the coffee rooms of Caffè dell'Ussero, historic meeting place founded on September 1, 1775.

Mural Tuttomondo: The modern mural is the last public work of Keith Haring, on the rear wall of the convent of the Church of Sant'Antonio, painted in June 1989.

Museo Nazionale di Palazzo Reale: exhibiting the belongings of the families that lived in the palace: paintings, statues, armors, etc.

Museo Nazionale degli Strumenti per il Calcolo: exhibiting a collection of instruments used in science, between whose a pneumatic machine of Van Musschenbroek and a compass probably belonged to Galileo Galilei.

Museo di storia naturale e del territorio dell'Università di Pisa, located in the Certosa di Calci, outside the city. It houses one of the largest cetacean skeletons collection in Europe.

Palazzo Blu : temporary exhibitions and cultural activities center, located in the Lungarno, in the heart of the old town, the palace is easy recognizable because it is the only blue building.

Construction of a new leaning tower of glass and steel 57 meters tall, containing offices and apartments was scheduled to start in summer 2004 and take 4 years. It was designed by Dante Oscar Benini and raised criticism.

The University of Pisa or Università di Pisa, is one of the oldest universities in Italy. It was formally founded on September 3, 1343 by an edict of Pope Clement VI, although there had been lectures on law in Pisa since the 11th century. The University has Europe's oldest academic botanical garden i.e. Orto botanico di Pisa, founded 1544.

Pisa has an international airport known as Pisa International Airport located in San Giusto neighborhood in Pisa. The airport has its own railway station and Pisa central railway station is 2 km (1.2 mi) away.

Pisa is a one-hour drive from Florence. You can also get a train directly to Florence from a Central rail station in Pisa (Pisa Centrale). Local buses connect the city of Pisa with all the neighboring cities (come to Pontedera, then take a bus for Volterra, San Miniato, etc.). Taxis come when requested from Pisa International Airport and Central Station.

Shooting was one of the first sports to have their own association in Pisa. The Società del Tiro a Segno di Pisa was founded on July 9, 1862. In 1885, they acquired their own training field. The shooting range was almost completely destroyed during World War II.

^"San Rossore Officially Sister City To Ocala". Thoroughbred Times. Retrieved 2007-07-16. "This event is just the beginning of a nice relationship between the city of Ocala and the city of Pisa and San Rossore," Fontanelli said in Italian during the ceremony.